Cell Reports (Jul 2024)

Arginine catabolism is essential to polymyxin dependence in Acinetobacter baumannii

  • Mei-Ling Han,
  • Yasser Alsaadi,
  • Jinxin Zhao,
  • Yan Zhu,
  • Jing Lu,
  • Xukai Jiang,
  • Wendong Ma,
  • Nitin A. Patil,
  • Rhys A. Dunstan,
  • Anton P. Le Brun,
  • Hasini Wickremasinghe,
  • Xiaohan Hu,
  • Yimin Wu,
  • Heidi H. Yu,
  • Jiping Wang,
  • Christopher K. Barlow,
  • Phillip J. Bergen,
  • Hsin-Hui Shen,
  • Trevor Lithgow,
  • Darren J. Creek,
  • Tony Velkov,
  • Jian Li

Journal volume & issue
Vol. 43, no. 7
p. 114410

Abstract

Read online

Summary: Polymyxins are often the only effective antibiotics against the “Critical” pathogen Acinetobacter baumannii. Worryingly, highly polymyxin-resistant A. baumannii displaying dependence on polymyxins has emerged in the clinic, leading to diagnosis and treatment failures. Here, we report that arginine metabolism is essential for polymyxin-dependent A. baumannii. Specifically, the arginine degradation pathway was significantly altered in polymyxin-dependent strains compared to wild-type strains, with critical metabolites (e.g., L-arginine and L-glutamate) severely depleted and expression of the astABCDE operon significantly increased. Supplementation of arginine increased bacterial metabolic activity and suppressed polymyxin dependence. Deletion of astA, the first gene in the arginine degradation pathway, decreased phosphatidylglycerol and increased phosphatidylethanolamine levels in the outer membrane, thereby reducing the interaction with polymyxins. This study elucidates the molecular mechanism by which arginine metabolism impacts polymyxin dependence in A. baumannii, underscoring its critical role in improving diagnosis and treatment of life-threatening infections caused by “undetectable” polymyxin-dependent A. baumannii.

Keywords